FIGURE 1.

Identification of GnT-IX-inhibitory activity in N2a cells. Effects of N2a cell lysate on GnT-IX (A) and GnT-V (B) activities, respectively. The lysate of the HEK 293T cells transfected with each construct was used as the enzyme source. Enzymatic activity was assayed in the presence of various quantities of N2a cell lysate with or without boiling for 3 min prior to assays. C, effects of de-N-glycosylation of the N2a cell lysate on its endogenous GnT-IX-inhibitory activity. N2a cell lysate (∼50 μg) was treated with PNGase F (0.5 unit) for 37 °C overnight prior to the assay and then assessed for its endogenous GnT-IX-inhibitory activity. All data are presented as the mean of duplicate measurements. Act., activity.